According to Helmut Siekmann the doubts regarding the ECB bond purchases could have consequences (Börse.ARD.de)

15. August 2017

The decision of the Federal Constitutional Court to pass on its concerns regarding the bond purchases of the European Central Bank (ECB) to the European Court of Justice (ECJ) in an extreme case could have far-reaching consequences according to Helmut Siekmann. The judges in Karlsruhe see good reasons for why the purchases of government bonds could constitute a breach of the monetary financing prohibition.

The Federal Constitutional Court has passed on several questions concerning the ECB's Public Sector Purchase Programme (PSPP) to the ECJ. As Helmut Siekmann explained in an interview with Börse.ARd.de, the judges in Luxembourg could decide that the Deutsche Bundesbank is no longer allowed to participate und in this case the German government would be obliged to take measures in order to stop the programme.